The present invention is directed to bicycles and, more particularly, to a bicycle power supply with reduced battery leakage.
Some recent bicycles have been equipped with electronically controllable electrical components such as derailleurs, suspension devices, displays, etc., along with the electrical controllers for such components. A well-known example of this technology is an automatic bicycle transmission that uses a speed sensor to automatically change gears according to bicycle speed. In all cases, a power supply is required to supply electricity to the various electronic components. Sometimes batteries are used for such power supplies. However, batteries need to be replaced when their electricity is consumed, and such replacement places undesirable burdens on the rider. Furthermore, the electrical components may suddenly stop operating when the batteries are depleted, which can be very problematic.
To avoid the above problems, some systems use a rechargeable battery as the power supply, wherein the rechargeable battery may be recharged using an alternating current generator mounted to the bicycle. Such a system is shown in JP 2001-245475. In this system, a rectifier converts current from an alternating current generator to direct current, and the direct current is used to charge a capacitor that functions as a battery unit. The capacitor typically comprises an electrolytic or double layer capacitor with a relatively large power storing capacity. Power from the capacitor then may be used to operate the various electrical components mounted on the bicycle.
In these systems, the microcomputers used to operate the various components typically include power conservation modes (e.g., SLEEP, HALT and STOP modes, etc.) in order to reduce electrical consumption during periods when the bicycle is parked, thereby prolonging the battery charge. However, even when operating in such modes, the micro-computer still consumes small amounts of electricity, and some electrical current leaks from the various electrical components connected to the microcomputer. This reduces the effectiveness of the power conservation modes and hence reduces the charge life of the battery.